Unopposed estrogen therapy causes endometrial hyperplasia (EH) and is associated with endometrial cancer (EC). Estrogen stimulates endometrial cells in the lining of the uterus to proliferate while progesterone tends to decrease this process. Human studies have shown that up to 75% women who develop EC, do so in the setting of EH. The longer the time and the more severe the EH, the more likely the evolution to EC. The possible link between a high soybean based diet and a low incidence of EC has been studied specifically and the few studies that have been done, do suggest that a high soybean based diet can help protect women from EC. It is the "phytoestrogen" content of the soybean that has been the compound of the most interest. Although studies on diet and EC have been performed, there have been no studies using isoflavone supplements specifically looking at prevention of EC or EH. In animal studies however, soybean isoflavones have been shown to reverse EH caused by estrogen. This study will use the red clover derived isoflavone, P-07 to examine its role in protecting women from EH and EC. Women between the ages of 45 and 50 will be studied specifically because they tend to have lower levels of progesterone than younger women and higher levels of estrogen than older menopausal women. This study is performed over a six month period but will help indicate whether further more long term studies on EH and phytoestrogens are warranted.